In the installation of adjustable Width metal door frame assemblies, it is conventional to put in place the frame elements, e.g. the jambs and the header, to adjust them to the thickness of the wall and then to fasten them to the wall using screws through the door casing into the wall. This is a relatively complex procedure when compared with the installation of a fixed width door frame. In the resultant frame, the screws through the casing are aesthetically undesirable so it is common practice to install caps over the casing. This is a further step that has to be taken in the installation and also requires six additional pieces in the overall frame assembly.
It is an aim of the present invention to provide an improved adjustable door frame that is relatively simple both in construction and installation and that does not suffer from the aesthetic problems of the prior art. The invention is also Concerned with a method of installing the frame.